Baijal Shruti, Srinivasan Narayanan
Centre of Behavioral and Cognitive Sciences, University of Allahabad, Allahabad 211002, India.
Cogn Process. 2010 Feb;11(1):31-8. doi: 10.1007/s10339-009-0272-0. Epub 2009 Jul 22.
Brain oscillatory activity is associated with different cognitive processes and plays a critical role in meditation. In this study, we investigated the temporal dynamics of oscillatory changes during Sahaj Samadhi meditation (a concentrative form of meditation that is part of Sudarshan Kriya yoga). EEG was recorded during Sudarshan Kriya yoga meditation for meditators and relaxation for controls. Spectral and coherence analysis was performed for the whole duration as well as specific blocks extracted from the initial, middle, and end portions of Sahaj Samadhi meditation or relaxation. The generation of distinct meditative states of consciousness was marked by distinct changes in spectral powers especially enhanced theta band activity during deep meditation in the frontal areas. Meditators also exhibited increased theta coherence compared to controls. The emergence of the slow frequency waves in the attention-related frontal regions provides strong support to the existing claims of frontal theta in producing meditative states along with trait effects in attentional processing. Interestingly, increased frontal theta activity was accompanied reduced activity (deactivation) in parietal-occipital areas signifying reduction in processing associated with self, space and, time.
脑振荡活动与不同的认知过程相关，并在冥想中起着关键作用。在本研究中，我们调查了萨哈佳三摩地冥想（一种专注形式的冥想，是苏达山克里亚瑜伽的一部分）期间振荡变化的时间动态。在苏达山克里亚瑜伽冥想期间记录冥想者的脑电图，同时记录对照组的放松状态脑电图。对整个时间段以及从萨哈佳三摩地冥想或放松的初始、中间和结束部分提取的特定时间段进行频谱和相干分析。不同冥想意识状态的产生以频谱功率的明显变化为标志，特别是在深度冥想时额叶区域的θ波段活动增强。与对照组相比，冥想者还表现出θ相干性增加。与注意力相关的额叶区域出现慢频率波，为额叶θ波在产生冥想状态以及注意力加工中的特质效应方面的现有观点提供了有力支持。有趣的是，额叶θ活动增加伴随着顶枕叶区域活动减少（失活），这表明与自我、空间和时间相关的加工减少。
